Rotary drum filter

Claim 1

A ROTARY DRUM FILTER HAVING A FILTRATE CYCLE INCLUDING AN ARCUATE DRUM PORTION WHEREIN SUB-ATMOSPHERIC PRESSURE IS APPLIED FOR FILTER CAKE ACCRETION AND AN ARCUATE DRUM PORTION WHEREIN SAID SUB-ATMOSPHERIC PRESSURE IS CUT OFF FOR FILTER CAKE REMOVAL, SAID FILTER COMPRISING: A ROTATABLE CYLINDRICAL DRUM HAVING A PAIR OF AXIALLY SPACED SERIES OF AXIALLY EXTENDING FILTRATE COMPARTMENTS ARRANGED IN THE FORM OF AN ANNULAR VOLUME ADJACENT THE PERIPHERY OF SAID DRUM AND CIRCLING SAID DRUM; EACH COMPARTMENT HAVING AN OPEN END LOCATED GENERALLY INTERMEDIATE THE ENDS OF SAID DRUM WITH SAID OPEN ENDS FORMING A SERIES OR BAND OF FILTRATE OUTLETS CIRCLING SAID DRUM; A PAIR OF AXIALLY SPACED CIRCULARLY EXTENDING WAYS MOUNTED ON SAID DRUM ADJACENT SAID FILTRATE OUTLETS; A STATIONARY VALVE POSITIONED OVER A PORTION OF SAID FILTRATE OUTLETS AND AT LEAST PARTLY EXTENDING AROUND THE PERIPHERY OF SAID DRUM WHERE THE SUBATMOSPHERIC PRESSURE IS CUT OFF FOR CO-OPERATION WITH SAID FILTRATE OUTLETS FOR CONTROL OF SAID SUB-ATMOSPHERIC PRESSURE DURING SAID CYCLE PORTIONS; SAID VALVE BEING SLIDABLY MOUNTED AND SUPPORTED ON SAID WAYS TO ALLOW SAID DRUM TO ROTATE WHILE SAID VALVE REMAINS STATIONARY; SAID WAYS HOLDING AND PREVENTING SAID VALVE FROM FALLING OR MOVING RADIALLY OR AXIALLY AWAY FROM ITS PROPER POSITION IN SAID WAYS; AND MEANS LOCATED INTERNALLY WITHIN SAID DRUM ANCHORING SAID STATIONARY VALVE AGAINST ROTATING WITH SAID DRUM.